Now we consider
Theorem 2 by Redko et al. [1]} for the source and target domains in our problem and merge Eq. (REF ) on Eq.(REF ) to conclude:
\(\begin{split}e_{\mathcal {T}}\le & e_{\mathcal {S}} +W(\hat{\mu }_{\mathcal {T}},\hat{\mu }_{\mathcal {S}})+e_{\mathcal {C^{\prime }}}(\mathbf {w}^*)+ (1-\rho ) \\&+ \sqrt{\big (2\log (\frac{1}{\xi })/\zeta \big )}\big (\sqrt{\frac{1}{N}}+\sqrt{\frac{1}{M}}\big ).\end{split}\) 
